Are there any relationship between hot set, permanent set and shrinkage for crosslinked polyethylene (XLPE)? I am wondering how a good hot set result will affect the shrinkage result. Or are there any suggestions as to how shrinkage of cable happened and to overcome it? Has it got to do with my side or my compound supplier side?

You should also be having regular discussions with the technical people from your XLPE resin supplier/ manufacturer. These folks are a very valuable and economical resource for you, as a customer, to use.

HST, Permanent Set or Cold Elongation Set and Shrinkage are three different tests. HST and PS can be combined as two parts of a single test, but shrinkage is a totally different test. The test temperature, the test duration and the testing method are all different.

The material definitely plays an important role in success of shrinkage test but processing techniques play just as much of an important role in the success of shrinkage test.

If you use pressure or hybrid tooling during extrusion of XLPE rather than tubing there are more chances that the test will pass.

If you are bound to use the tubing technique due to sector shaped conductor or due to taped conductor, use vacuum behind the cross head and hot water in first trough.

During testing put the test samples in talcum powder rather than putting them on frame.

Hi there Sahota and thank you very much for the information. One small point:

Your statement "If you are bound to use the tubing technique due to sector shaped conductor or due to taped conductor, use vacuum behind the cross head and hot water in first trough." refers to a moisture cure XLPE compound instead of the standard CV type, peroxide bearing XLPE compound where pressure extrusion is the norm.